inline FLEX_ALWAYS_INLINE_FLATTEN void operator()(flex_date_time& t, const flex_float u) const {
int64_t integral_part = std::floor(u);
int64_t us_part = (u - integral_part) * flex_date_time::MICROSECONDS_PER_SECOND;
t.set_posix_timestamp(t.posix_timestamp() - integral_part);
auto microsecond = t.microsecond() - us_part;
if (microsecond < 0) {
t.set_posix_timestamp(t.posix_timestamp() - 1);
microsecond += flex_date_time::MICROSECONDS_PER_SECOND;
}
t.set_microsecond(microsecond);
}
inline FLEX_ALWAYS_INLINE_FLATTEN void operator()(flex_date_time& t, const flex_int u) const { t.set_posix_timestamp(t.posix_timestamp() - u); }